Composite sintered material having sandwich structure.

摘要

A composite sintered material having a sandwich structure is composed of a hard layer of a sintered diamond compact sandwiched between a pair of substrates and is suitably used as a material for drill.

The composite sintered material having a sandwich structure consists essentially of:
<UnorderedLists id="ula01" listStyle="none"><ListItem>a hard layer composed of sintered diamond compact;</ListItem><ListItem>a pair of intermediate layers each having a thickness of 10 to 500 microns and bonded respectively to one of the opposite surfaces of said hard layer, each of said intermediate layers consisting of a material which has a thermal expansion coefficient of 3.0 x 10-<Sup>6</Sup> to 6.0 x 10<Sup>-6</Sup>/ °C and prevents the transfer of the iron group metal therethrough in the course of the sintering of the hard layer;</ListItem><ListItem>a pair of substrates bonded respectively to one of the surfaces of said intermediate layers to form a sandwich construction with the hard layer and composed of a metal or alloy having a thermal expansion coefficient lower than 6.0x10<Sup>-6</Sup>/°C.</ListItem></UnorderedLists>

In case the composite sintered material is used as a blade tip for cutting tool, the sintered diamond compact contains preferably 5 to 15 vol% of an iron group metal and the balance being of diamond particles, and each of the substrates is composed of a sintered alloy mainly composed of WC and/or MoC having a thermal expansion coefficient lower than 4.6 x 10-6/ °C.